BIBLIOGRAPHY OP PUBLICATIONS OF ISAAC LEA, LL. D. 63 



99. 



Idri3. Lea, Isaac. [On a specimen of Gneiss bored by Pholas dactylus.] <^rroc. 

 Acad. Xa t. Sci. , Pliila. , vi , p. 438. No. 12. 



Verbal communicatiou made December 13, 1853. (See Proc. Amcr. Philos. Soc, vi, p. 7.) 



100. 



1854. Lea, Isaac. [On AcosUea Giiachiasana, D'Orbijjny. ] <^Proc. Acad. Nat. Sci., 

 Phila., vii, pp. 1-2. No. 1, January and February, 18.54. 



Verbal communication made January 3, 1854. (See Proc. Amer. Philos. Soc.,vi, p. 20.) 



101. 



1854. Lea, Isaac. Rectification of Mr. T. A. Conrad's "Synopsis of the Family of 

 Naiades of Nortli America," published in the "Proceedings of the Academy 

 of Natural Sciences of Philadelphia, Februarj', 1853." <^Proc. Acad. Nat. Sci., 

 Phila. , vii, pp. 236-249. No. 6, Nov. and Dec, 1854. 



Read before the Academy Natural Sciences, Phila., February 7, 1854. 



(See Proc. Amer. Philos. Soc, vi, p. 83.) 



Separate as follows: 



Eectification [ of | Mr. T. A. Conrad".s | " Synop.sis of the Family of Naiades of North 

 America," | published in the | "Proceedings of the Academy of Natural Sciences | of Phila- 

 delphia, I February 1853," | by | Isaac Lea. | — | Philadelphia. | Merrihew and Thomp.son, 

 Printers, | Merchant Street, above Fourth. | 1854. 12°. pp. 16. Pamphlet. 



Received by the Academy Natural Sciences on or before February 6, 1855. (See Proc. 

 Acad. Kat. Sci., Phila., vii, p. xxii ) 



"Finding in it numerous errors in regard to the dates of my memoirs and the synonymy 

 of my species, I desire that the correction of part at least of these errors may reach the sci- 

 entific public bj' the same channel." 



"I do not mean to correct the synonymy of this Synopsis, but I trust to satisfy every one 

 that it can bo of no value whatever where the dates are so erroneously stated." 



"He usually takes the date of the title of the Volume of the Transactions of the American 

 Philosophical Society, where the species may have been described, while the volumes pub- 

 lished by the Society, as they are almost universally by all scientific bodies, were really 

 issued in parts at different times, and generally in three parts. Thus when part first of any 

 volume was issued, the Society distributed copies immediately to their subscribers and to all 

 the principal societies in Euroi^e and in this country ; and, when I have had in such part a 

 memoir, I had two huudrt d and fifty copies printed for my own use, one hundred and fifty of 

 which I at once distributed at homo and abroad where I thought they might be useful to 

 science. When part second of the same volume may have been printed the same process 

 took place, and when part third was rea y it took the same course, with this addition, viz, 

 a title-page for the whole volume was printed for the convenience of those who might choose 

 to have their three parts bound into a volume, and this title boro the date of the last part. 

 Thus most of these copies of my descriptions, with figures, may have been in the hands of 

 the zoologists of Euriipo and America for two or three years prior to the date at which Mr. 

 Conrad has stated them as being published. In addition, he usually pays no regard to the 

 dates of my descriptions printed in the Proceedings of the American Philosophical Society 

 or otlierwise, prior to tlicir sub.seqnent issue in the Transactions. Tliuson the 18th August 

 1843, 1 read a number of descriptions before that society, and permission was granted to me to 

 print them at once. The following day, August 19th, these descriptions were printed and 

 circulated. Now Mr. Conrad in his synopsis dates these as published in 1840! three years 

 after they were actually issued printed." 



"The question as to fixing with precision the date of discovery of a new form, has been 

 one of anxiety and doubt among men of science. For myself I have never felt satisfied that 

 it was judicious to make any change in the long received rule of perm;;nently fixing the date 

 of publicafiim to bo that, when the paper was read before and deposited with the officers of 

 a learned society, with a view to i)rinting." 



"Receiving as authority the dates issued by individuals in publications is exceedingly 

 dangerous. There may bo antedates, and these can rarely be detected. In the case of a 

 deposit of a paper with a learned society, intended for publication, and a record being made 

 of it at the time, there cannot be any probability by collusion of the oliicers to make a 

 change." 



